Dual roles for the Mss116 cofactor during splicing of the ai5γ group II intron
| Autor: | Amanda Solem, Nora Zingler, Anna Marie Pyle |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Saccharomyces cerevisiae Proteins
RNA Splicing Neurospora crassa DEAD-box RNA Helicases Fungal Proteins 03 medical and health sciences Exon Genetics 030304 developmental biology 0303 health sciences Fungal protein Splice site mutation biology Nucleic Acid Enzymes 030302 biochemistry & molecular biology Intron Helicase Exons Group II intron biology.organism_classification Introns Kinetics Mutation RNA splicing biology.protein Nucleic Acid Conformation Salts |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| DOI: | 10.1093/nar/gkq530 |
| Popis: | The autocatalytic group II intron ai5γ from Saccharomyces cerevisiae self-splices under high-salt conditions in vitro, but requires the assistance of the DEAD-box protein Mss116 in vivo and under near-physiological conditions in vitro. Here, we show that Mss116 influences the folding mechanism in several ways. By comparing intron precursor RNAs with long (∼300 nt) and short (∼20 nt) exons, we observe that long exon sequences are a major obstacle for self-splicing in vitro. Kinetic analysis indicates that Mss116 not only mitigates the inhibitory effects of long exons, but also assists folding of the intron core. Moreover, a mutation in conserved Motif III that impairs unwinding activity (SAT → AAA) only affects the construct with long exons, suggesting helicase unwinding during exon unfolding, but not in intron folding. Strong parallels between Mss116 and the related protein Cyt-19 from Neurospora crassa suggest that these proteins form a subclass of DEAD-box proteins that possess a versatile repertoire of diverse activities for resolving the folding problems of large RNAs. |
| Databáze: | OpenAIRE |
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